Consciousness signature warns of awareness during surgery

ANAESTHETIC wearing off mid-operation is not just the stuff of nightmares – it occurs in around 0.2 per cent of surgeries globally. But keeping tabs on the brain during surgery could stop this.

To look for a signature of consciousness that could be monitored during surgery, Emery Brown at the Massachusetts Institute of Technology and his team attached an EEG cap to the heads of 10 adults and measured changes in brain activity as unconsciousness was induced using a general anaesthetic.

As the volunteers lost and regained consciousness they were asked to press a button whenever they heard a click. By matching brain activity with the stages of wakefulness, the team identified patterns that corresponded to different levels of consciousness, allowing them to tell when someone was waking up (PNAS, DOI: 10.1073/pnas.1221180110).

This article appeared in print under the headline "How to stop people waking in surgery"

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